A printed circuit board (PCB) plays a very important role in many high-tech electronic products related to information industry. The conventional flat cable arrangement in PCB has been gradually replaced by a flexible printed circuit board (FPCB), the development of which has largely upgraded the technical level of electronic industry. FPCB includes a flexible substrate formed of copper foil, which is processed to directly arrange circuits thereon. The electronic and information industries also keep researching and developing circuit capacity that enables electric and electronic products to have small volume and reduced weight, and electronic components to be highly densely arranged on a circuit board. For this purpose, there are developed multilayer PCBs with multiple layers of rigid circuit boards (FPCBs) and flexible circuit boards (FPCBs), so as to increase the area on the circuit board for arranging circuits. Many advanced electronic products, such as mobile phones, notebook computers, and GPS (global positioning system) navigation systems, have adopted the multilayer circuit board technique.
While the multilayer circuit board has combined multiple layers of RPCBs and FPCBs to increase the area for arranging circuits, circuit arrangement at some bent areas still requires flexible cables. Even in some advanced wiring techniques, flexible cables are used along with RPCBs to achieve connection of two rigid circuit boards at bent portion.
Generally, the conventional PCB may be formed in two ways, namely, milling and stamping. In forming the PCB with stamping dies, a raw material for the circuit board is stamped independently, unnecessary leftovers are trimmed off, and the circuit board is removed from the stamped material by bending broken connecting points formed on the material. The leftovers produced during the forming of the circuit board would cause environmental pollution and waste of material.
The conventional circuit board requires precision manufacturing technique, and the FPCB thereof tends to crimp and produce surface folds when it is pressed and bonded to the FPCB. It also requires high precision technique to directly arrange circuits on the FPCB. Poor control in the manufacturing process would endanger the circuits on the FPCB or even destroy the whole FPCB. When the circuit board has all four edges remove therefrom, it does not provide any point of strength for supporting it, and the conventional microgroove V-cut processing technique can only be used to process the circuit board with limit to its operating direction.